Lathe question for makers

[Davy Stephenson]

Bill wrote:

Also, because of the way CNC tooling/machining works, and the way the tool approaches the work, you don't get as good a surface finish as you can with hand turning techniques on a toolrest. I reckon that without very careful custom cutter making, CNC-made mounts might look a bit rough under close inspection.

DDS

I dissagree with the reckoning and might be aspects here, I have had some student chanters made by our local violin maker, who has a 4-D milling/turning station, which makes a wonderful job of turning the outside of both keyed and non keyed chanters, and the finish is very good indeed, with the minimum of final polishing needed.

The big bug bear is the setting up time for each object, especially the keyed version, by the time it takes to set up I can just about turn one freehand in about the same time.

I served my time as a motorcycle engineer where we had some of the very early cnc machines, although they were pretty primitive and a lot slower than those of today, the principle is exaclty the same, and one would have to make an awfull lot of chanters and money to pay for a machine that is going to do only one job.

I do however totally agree that no machine can mimic the pure skills of hand turning, the asthetic curves and lines are simply not there when done on a metal lathe, that's my opinion only.

It takes many years to master hand turning techniques, some of which will never have what it takes to get that desired look, especially by trying to use a metalwork lathe for turning what is basically a woodwork lathe job.

Of course you can remove the toolpost from a metal lathe and replace it with a haqnd rest, but its still not the same, one cannot reach and turn smoothly because you are restricted by the bulk of the machine.

A traditional looking set of uilleann pipes, need no fancy machines to make them.

A little bit of knowledge can be very dangerous.

[billh]

...

I dissagree with the reckoning and might be aspects here, I have had some student chanters made by our local violin maker, who has a 4-D milling/turning station, which makes a wonderful job of turning the outside of both keyed and non keyed chanters, and the finish is very good indeed, with the minimum of final polishing needed.

(As you of course are well aware), in hand-turning, the tool angle can be adjusted all the way around complex curves, to keep the perfect relationship between bevel and work. This cannot be done with most CNC machines. Possibly some 4-D machines can do it, but these are beyond the reach of most individuals. Even if you had a machine with the capability to do this, I expect the programming required to keep the tool angle optimal all the way 'round the piece would be difficult. (Some CNC software may be able to do this automatically but, again, the software price then becomes the obstacle)....

I do however totally agree that no machine can mimic the pure skills of hand turning, the asthetic curves and lines are simply not there when done on a metal lathe, that's my opinion only.

Agreed except the "when done on a metal lathe" part. I would say "when done using machining techniques".

Of course you can remove the toolpost from a metal lathe and replace it with a haqnd rest, but its still not the same, one cannot reach and turn smoothly because you are restricted by the bulk of the machine.

I do not find this to be the case. The only difficulty with metal lathes is the limit on turning speed - which can of course be remedied with small modifications to the lathe to enable higher speed operation (especially with belt-drive machines). Then again - the old makers may not, as you point out, have had "fancy machines" but they managed excellent quality (by treadling) at speeds slower than a modern metal lathe. Those old lathes incorporate a number of features which we today associate with 'metal lathes' - at the time there was no such distinction. A wider hand rest would be 'nice to have' but in practice I haven't been compelled to make one.

Bill

[Davy Stephenson]

Yeah Yeah !

[John Mulhern]

restraint...restraint..arrrrrrrrgh, must resist urge to stand on soap box... too late!

Those small desk & benchtop machines look cute, but more often than not they don't use industry standard Fanuc G code...which may be why they're using operator interfaced conversational programming. This becomes important if you're planning on programming complicated parts using a CAD CAM post processor which generates standard G code from your drawings. Also, I don't know how well those small machines hold repeatable tolerances. That Boxford appears to be a substantial machine by a reputable maker...but other than the high quality Austrian EMCO lathes, I suspect most of them are just demonstration platforms for an educational environment.
On the other end of the garage/hobby shop spectrum there's the Haas TL-1...oooooh baby! They start at $20K USD and treat every damn basic lathe necessity as an over-priced option (tailstock, coolant, etc.), and quickly vanish further into unaffordability.
OTOH, that CNC Zone site that Harlow mentioned is way cool & the homebuilt combinative possibilities of a cheapo Chinese 1236 or 1440 manual metal lathe, some inexpensive rolled ballscrews & servo motors, and a PC running Mach 3, has intrigued me for a couple years. The strong probability of a factory mis-aligned headstock & Chinese spindle bearings turning to pixie dust is a sobering reality check.
I agree with Bill, though. Relevant to pipemaking, I think CNC would be especially handy for precisely turning irregularly tapered bore reamers, or for 3D milling of chanter keys out of billet. McClellan's been turning out GHB chanters for some time on a CNC lathe. I can't find his link at the moment, but there was a pic on Mr. McClellan's website of turning a blackwood GHB chanter using a VNMG carbide insert in a neutral holder & I thought the results were quite nice. Probably need a bit of touching up in the areas the insert's nose radius couldn't reach...but still...


BTW...nice YouTube videos, Davy! ...more please...maybe tube bending & key making?

[Davy Stephenson]

Ahhhh yes, I suppose I will have to bendeth knee and bow to the sheer migtyness of him, NOT, head to head not really, just two different opinions, Oh well, only time will tell, I say make the best out of what you have got, nothing else matters, bury the hatchet of course.

Joking aside, everyone has there own way of doing things, it doesn't matter how the finished product comes out, as long as it works well and you get no come backs, Uilleann pipe making is still not standardised compared to highland pipes, they are as much standardised as your going to get, ready made reeds off of the shelf etc.

CNC Davy as it has been said is as far from them as you can imagine
but there is no harm in trying different things, CNC definately has its slot when making the smaller components of pipes or whatever.

A little bit of knowledge can be very dangerous

[J-dub]

Davy, thanks for the info about your experiences with using CNC to turn chanters. I would have assumed the same point that Bill made - that a single-point CNC tool would have a difficult time getting as good a surface finish "off the tool" as hand turning. It is nice to know someone has actually tried this But, as you said, an experienced hand can turn it out in about in the same time.

CNC for reamer making is another matter, of course. I have been looking it as well...

Those small desk & benchtop machines look cute, but more often than not they don't use industry standard Fanuc G code...which may be why they're using operator interfaced conversational programming. This becomes important if you're planning on programming complicated parts using a CAD CAM post processor which generates standard G code from your drawings. Also, I don't know how well those small machines hold repeatable tolerances. That Boxford appears to be a substantial machine by a reputable maker...but other than the high quality Austrian EMCO lathes, I suspect most of them are just demonstration platforms for an educational environment.

Thanks for that bit, John. I looked into some of those stand alone type machines, but I would like to be able to go from Solid Works into Fanuc G. I figured that those stand alone units would get frustrating enough when trying to reproduce a reamer profile that I would just end up doing it as I do now on my Logan, cut steps using the cross feed and carriage micrometers and smooth it all out with a file!

John, it's funny you mentioned the quality of the Austrian made EMCO lathes...cause in a major stroke of increadible luck I just picked one up Saturday! Had to drive 400 miles round trip to get it, but for what I piad for it it was more than worth the effort, literally penny's on the dollar because this seller is in eastern Idaho and did not want to deal with shipping the lathe/mill. It has the the milling head and nealry all the accessories (but no dividing/rotary table unfortuneatly). I hope at some point that I can convert this baby into a CNC for turning reamers and milling the cutting flutes. Whoopie! Sorry, I can't resist a bit of tool gloating since I am always a day late and a dollar short when it comes to deals on machinery.

In case anyone is interested about these lathes, there are some pics on Lathes.uk...

http://www.lathes.co.uk/emco/page4.html

If you or Harlow (or anyone for that matter) have anymore sources for info on CNC-related conversions I would be most grateful. Thanks.

John

[John Mulhern]

Nice snag!
Those guys on the CNC Zone forum have been converting everything but their grandma's shopping carts, (routers, plasma cutters, lathes, mills), with rolled ballscrews, steppers or servos, and PC based controls. That'd really be the best place to start.
SolidWorks should do ya fine.
How big is the spindle bore through-hole? My little Atlas has a .535" bore...barely adequate and I wish it was a bit bigger. I have mixed feelings about any 3-in-1 machine's milling rigidity for tool steel. Even with the milling head scrunched down for max rigidity, going much beyond the carriage base might require some creative fixturing to minimize chatter...maybe light passes? dunno. I couldn't go much beyond .020"-.030" per pass on my 700 pound mill/drill with a full length reamer stuck up in the air, even with supports in the middle.
Here's a website I stumbled across a couple weeks ago. Making (and heat treating) multi-fluted O-1 chambering reamers on an inexpensive Chinese mini-lathe & mill/drill . Kinda cool!,,,although heat treating a reamer that's spinning in a drill chuck is kind of a YIKES!!! lol
(7 part - slow pic download)
http://personal.geeksnet.com/soderstrom ... eamers.htm

http://www.cnczone.com/forums/forumdisp ... 7c5e&f=221

[J-dub]

Thanks for th info John. Wow, that CNC forum is enormous! I am familiar with a lot of what's required through my day job, but I don't know when (or if) I will ever find time and motivation to go the CNC route at home - I would rather make pipes at this point

I did an extensive info search about the Emco maximat lathe/mill before I bought it, but I never thought I would ever find one, especially for the price I paid. They were designed as a compact tool room grade machine. Even though they are small in size they are capable of taking suprisingly heavy cuts in tool steel because of the rigidity of the machine. Manufactured to very high tolerances, very Ausrtrian! Lash and end play can be eliminated in all axis, even the spindle pre-load can be adjusted for wear. Spindle runout is less than 0.0002"! All the slides move silky smooth eventhough the machine has been dormant for 15 years. The spindle hole ~30 mm. it is big enough for a 2MT collet with a 25/32" capacity collet. The lathe bed will hold ~18" between centers (more if useing through collets), long enough for reamers. The lathe has a great range of spindle speeds between 45 rpm and 2500 rpm (as fast as most wood lathes top out at). It can do metric, module and english threading. The metric will come in handy for making bicycle parts.

The milling head is really massive and can supposedly take pretty heavy cuts in steel for it's size, although it only has 4 speeds to choose from. Based on what another owner of a maximat told me, I should be able to cut reamers in maybe three passes, if, as you noted, the reamer blank is supported well enough. I do need to come up with a better method of holding the work. I like your solution, now that I have the milling capacity I can make me some of dem fixtures! Another nice feature: The work is fixed to the lathe carriage and can be fed via power feed when milling. From my exerience I find that using power feed helps increase the rate of metal removal a little, probably becasue there is a more consistent and even load on the cutter than by hand milling, I don't know?

I would like to have a full size milling machine some day, preferable old American iron, but I have looked locally for close to two years and there has been nothing suitable. Lots of good old iron in New England, and some in So Cal, but it costs a fortune to have a 3,000 lb machine moved cross country these days

That reamer making article is a new one to me, really great stuff. Turning the part in the drill press while heating with the Oxy/acetylene torch is a little I tried hardening a full length reamer once using my oxy/acetylene rig, but I just hung the reamer from a wire and it was difficult to heat uniformly to non-magnetic without over-cooking some areas and underheating others. Plus I did not really have an adequately long oil container to quench in. The net result was that it warped a little. I have not been hardening my reamers since then, but I think I might try again now that I am making them in more manageable sections - plus I want to try the drill press methhod just to create a potentially more dangerous enviroment in the shop, just for thrills

Cheers!
John

[billh]

Hmm, heavy cuts...

Some time ago I took a set of reamers which I'd turned to complex profiles to a local machinist, to mill them into D shapes. He had some quite big machines capable of heavy cuts... but although he's very experienced, the reamers ended up damaged/distorted by the process, the smallest reamer was totally destroyed. So there's a limit to how heavy-handed you can be with these cuts - probably the limiting factors are the rigidity of the reamers (not that rigid, given that they are untreated silver-steel) and the rigidity of the clamping setup.

In the end this is the experience that convinced me to buy the "micro mill" which despite its small size was capable of milling the reamers to a D profile, using relatively light cuts. It's slower, true - it takes me over an hour to mill down a big reamer (with a 6mm end mill, running about 300RPM), but it beats grinding or hacksaws, and only takes a little bit of bench space. A big mill would be nice, but the tool cutting speed is limited by the type of steel used in any case ("silver steel", which is what I use, apparently classes as a "high carbon" steel for these purposes).

Bill

[J-dub]

Bill, I think I recall seeing a pic of your milling set-up on your web site. Don't you have the reamer clamped directly to the table? I would think that it is sufficiently held in place that you could remove metal a little more vigorously. What brand/type of milling cutter are you using? I have found, not suprisingly I guess, that there is a very big difference between the capability of various end mills when it comes to removal rates, and it is dependent on what type of drill rod you are using (O-1 vs. air quenching A-2). I can't remeber what class endmill I have had the best results with off the top of my head, I'll check when I get home. An advantage of having a very slow low end (~50 rpm) is that you can go the route of slower speed and bigger feed (slow, big it's all relative man ), which seems to be a good rule of thumb.

But I agree that patience is a virtue when it comes to avoiding ruining a reamer blank that has so much work in it already. I am just so impatience though, I always have to see how far I can push things before calamity strikes- just ask my wife

In the end this is the experience that convinced me to buy the "micro mill"

Ya, I think this in a nut shell exemplifies probably the best advice/word of caution for any would-be pipe makers, regardless of whether one's ambitions are amateur or professional - be prepared to do everything yourself - it's a great occupation for anal retentive control freaks who should be cloistered away from the rest of society anyways ! There is a lot more to it than skill turning wood and what type of lathe you have to work with. In this regard I think that the methods employed and the equipment used for pipe making have not "advanced" much since to the days of Kenna, Egan, Coyne, and I like it that way.

As you pointed out earlier, and I whole-heartedly agree with you...

Then again - the old makers may not, as you point out, have had "fancy machines" but they managed excellent quality (by treadling) at speeds slower than a modern metal lathe. Those old lathes incorporate a number of features which we today associate with 'metal lathes' - at the time there was no such distinction.

There are a lot of unusual work-holding problems in pipemaking, and in the making of the necessary tools. For me, learning traditional (and non-traditional) methods and approaches to machining have been every bit as useful to me as learning the art of wood turning.

Cheers!
John